This invention relates to a lifesaving device and, more particularly, to a lifesaving device carried by a vessel or the like that can be released and floated on the surface of water in case of distress, allowing crews and passengers to be buoyed up until help arrives.
Vessels for sea or lake cruising are obliged to equip certain legal apparatus under the Ship Safety Law and life appliances are of particular importance among them. The details for the life appliances are defined by the Regulation for the Ship-borne Lifesaving Appliance. More specifically, the type(s) and the number of the appliances that should be equipped on a vessel are fully defined for the individual vessel depending on its type, purpose and capacity as well as where it travels. The life appliances can be classified generally into two groups:
(1) water-borne or floating appliances; and
(2) signal apparatus for rescue.
The floating apparatus defined by law includes lifeboats, life rafts, buoyant apparatus, life buoys and life jackets.
Typical buoyant apparatus used as a lifesaving device comprises a block-like floating buoy. The block-like floating buoy has, as a buoy body, an air-tight box made of metal plates having sufficient corrosion resistance and a life line is passed around the buoy body. The buoyant apparatus is held in a predetermined position of the deck side on a vessel and is launched into water in an emergency. Crews and passengers can float in water while holding the life line and wait for rescue with an assistance of the buoyancy force.
Specifications for the buoyant apparatus defined by the Regulation for the Ship-borne Lifesaving Appliance require that at least eight persons can be buoyed up by a single buoyant apparatus having a predetermined peripheral length and sufficient buoyancy force to buoy the victims positively. The buoyant apparatus just after being launched is ought to be linked to the vessel in distress through a painter. In addition, to equip the life line along the periphery of the buoyant apparatus is also one of the requirements obliged by the Regulation for the Ship-borne Lifesaving Appliance.
The buoyant apparatus is classified into a non-inflatable type and an inflatable type according to the structure of the buoy body. The non-inflatable buoyant apparatus may comprise the above mentioned air-tight block made of metal. Alternatively, it is made essentially of a material lighter than water including woods such as balsa and kapok and a closed cell or (expanded) vinyl sponge. On the contrary, typical inflatable buoyant apparatus is composed of a rubber bag or the like held in deflated condition in an enclosure and inflated in an emergency with injected gas.
The buoyant apparatus used as the lifesaving device should have a predetermined floating capacity to ensure the buoyancy sufficient for the victims, i.e., 14.5 kg for one person. Besides, the outer periphery of the floating buoyant apparatus should exceed a predetermined length to ensure sufficient space for the victims to hold the life line. With this respect, each vessel or ship is obliged to equip the buoyant apparatus having enough capacity to obtain sufficient buoyancy force for the maximum number of persons on board. Accordingly, the non-inflatable buoyant apparatus, if being used, occupies a large portion of the free-space on the narrow deck because it is carried in a predetermined stowed away position at the deck side. This means that the space required for the buoyant apparatus, where otherwise is used effectively for other equipment, significantly restricts a design or a layout of the vessel.
On the contrary, the inflatable buoyant apparatus has no problem regarding to the spacing. However, a bag having relatively large capacity must be inflated to the extent that a predetermined peripheral length can be obtained. The inflatable buoyant apparatus is thus normally stowed away together with a source of pressurized gas for inflating it. This source is relatively large in dimension and has a disadvantage of increasing the total weight of the inflatable buoyant apparatus.